Production and utilization of vacuum



y 1965 s. A. J. LILJENDAHL 3,181,553

PRODUCTION AND UTILIZATION OF VACUUM Filed May 2'7, 1959 4 Sheets-Sheet l May 4, 1965 Filed May 27, 1959 4 Sheets-Sheet 2 i) 1965 s. A. J. LILJENDAHL 3,

PRODUCTiON AND UTILIZATION OF VACUUM Filed May 27, 1959 4 Sheets-Sheet 3 III III

III

y 1965 s. A. J. LILJENDAHL 3,181,553

PRODUCTION AND UTILIZATION OF VACUUM Filed May 27, 1959 4 Sheets-Sheet 4 Fig.7

United States Patent 3,181,553 PRODUCTION AND UTILIZATION OF VACUUM Sven Algot Joel Liljendahl, Gyllenstiernas Vag 8, Staket, Sweden Filed May 27, 1959, Ser. No. 816,131

Claims priority, application Sweden, May 28, 1958,

5,100/58 9 Claims. (Cl. 137-657) The present invention is concerned primarily with the problem of utilizing the potential energy of a liquid for the direct production of vacuum within a closed vessel.

One object of the invention is to provide an improved hydraulically operated gas pump of the kind in which iquid is introduced batchwise into the top end of a standpipe or standpipes so as to form therein spaced successive liquid bodies or plugs filling out the cross-sectional area of said pipe or pipes and removing between them gas from an enclosure communicating with said standpipe or standpipes.

A particularly important object of the invention is to provide a hydraulic gas pump of the kind referred to which, without reduction of its efiiciency, can be designed for high pumping capacity, i.e. with a standpipe or standpipes of substantial cross-sectional area, for instance for use of the potential energy of high natural heads of water.

A further object of the invention is to provide a hydraulic air pump of a simple construction in which the potential energy of waste or sewage water discharged from the upper floors of a building into a sewer or any other outlet conduit can be utilized for producing a vacuum.

Another object of the invention is to utilize a vacuum produced in this or in any other way for sucking domestic sewage onward through substantially horizontally disposed conduit sections, t-hus eliminating the usual require ment for a steep slope towards the outlet end of such conduit sections, and enabling the conduits concerned to be narrower than has been possible before.

According to this invention, there is provided a hydraulically operated gas pump, particularly a vacuum pump, in which liquid is introduced batchwise into the top end of a standpipe so as to form therein spaced successive liquid plugs completely filling out the cross-sect-ional area of the pipe and adapted to carry away between them gas withdrawn from an enclosure communicating with the standpipe, wherein, for controlling the amount of liquid supplied to the standpipe in each batch, the standpipe is provided at its top end with a valve adapted to open and close periodically, and a branch pipe communicating with the enclosure to be evacuated is connected to the stand-pipe downstream of said valve.

Further features and advantages of the invention will become apparent from the following detailed description of preferred embodiments and applications thereof given by way of example with reference to the accompanying drawings, in which:

FIGURES l, 2 and 3 show diagrammatically one embodiment of hydraulic gas pump according to the invention in different stages of its operating cycle;

FIGURE 4 illustrates diagrammatically a modified hydraulic gas pump;

FIGURE 5 shows a vertical section through a hydraulic gas pump comprising a closed float vessel and an influent inlet connected thereto and containing a float-controlled cut-off valve;

FIGURE 6 shows a vertical section through a building in which a plurality of vacuum-producing apparatus ac cording to FIGURE 5 are installed, such apparatus being adapted to be operated by sewage supplied from the overlying floors;

FIGURE 7 is a diagrammatic vertical section through apparatus for producing vacuum utilizing the potential energy of a natural water basin or stream; and

FIGURE 8 is a side view of a valve assembly useful in the pump arrangement of FIGURE 5.

Referring to FIGURES 1 to 3 of the drawings, numeral 10 designates an open-topped vessel or receptacle communicating through a central bottom opening with a substantially vertical standpipe 11, the bottom end of which is submerged below the surface of a water pool 12. Disposed in the receptacle 10 is a float 13 formed at its bottom end with a conical valve member 14 adapted, when the float is in its lowermost position, to rest on a conical valve seat 15 formed around the bottom opening of the float vessel 10. The float 13 is slidably guided in the float vessel by guide ribs 16 provided on the inner wall surface of the vessel. Numeral l7 designates an inlet through which water or any other liquid is fed continually or batchwise into the float vessel.

Opening into the vertical standpipe 11 immediately below the fioat vessel It is a branch pipe 18 which cornmunicates with a closed vessel or enclosure (not shown) of comparatively large capacity and in which a vacuum is to be maintained. Inserted in the branch pipe 18 adjacent to the standpipe 11 is a non-return valve 19 which opens towards the standpipe so as to permit the flow of air from the enclosure into the standpipe, but prevent the flow of air or Water from the standpipe into the enclosure.

The vacuum-producing apparatus described operates as follows.

A certain degree of vacuum is assumed to prevail within the large closed vessel with which the branch pipe 18 communicates. Consequently, a liquid column 20 of the height h is established in the standpipe 11. The float vessel It is assumed to be only partially filled with liquid, so that the float 13 will be in its lowermost position in which the bottom opening of the float vessel is closed.

In this position the float 13 is acted on by a downwardly directed force established by the sum of the weight of the float and the suction head caused by the vacuum existing in the standpipe and acting on the area or" the conical valve member 14 exposed to the interior of the standpipe 11, less an upwardly directed force which is proportional to the mass-weight of the body of water displaced by the float. As the liquid level rises within the float vessel 10 this mass-weight will increase, and finally a point will be reached at which the upwardly directed force exerted on the float by the liquid body concerned will exceed the sum of the downwardly directed forces. At this moment the fioat will begin to move upwardly. When the float has risen to an extent allowing liquid to enter the standpipe 11, such liquid will compensate for the suction acting on the exposed bottom face of the valve member so that the suction will rapidly diminish or cease, thus causing a sudden decrease of the total downward force exerted on the float. As a consequence the float will rapidly be lifted to the position determined by the quantity of liquid present within the float vessel It), thus completely uncovering the bottom opening of the float vessel.

Liquid from the float vessel It) will now rapidly flow into the standpipe 11, whilst forming therein a liquid plug or piston 21 completely filling out the cross-sectional area of the standpipe. The inflow is initially accelerated by the vacuum prevailing in the standpipe 11 above the liquid column 20. As, under the action of gravity, the liquid plug 21 drops deeper down the standpipe 11 at an accelerated velocity, the pressure of the volume of air, 22, trapped between the liquid plug 21 and the liquid column 20 will be increased, thus causing the liquid column 2%) to begin to fall within the standpipe 11. At the same time the liquid level within the float vessel 10 will sink causing the float 13 to move downwardly and, finally, to 7 seat its bottom end forming the conical valve member 14 on the valve seating 15, whereby the downflow of liquid into the standpipe will be interrupted. .Now,'-if the capacity of the float vessel 10 has been suitably dimensioned, a sufficient quantity of liquid will have been admitted into the standpipe'll to cause the length of the liquid plug 21 formed therein to be considerably in excess of the original height h of the liquid column 20. Therefore, the liquid plug 21 will continue to drop down the pipe 11 whilst displacing the entire liquid column 2% and the volume of air, 2-2, on top of this column and will itself occupy the place previously occupied bythe liquid column 20.

When, in the sequence of events just described, liquid from theflo-at vessel 10 entered the st-andpipe 11 tending to increase the pressure therein, and, because this pressure is directed toward the pipe 1 8, this will cause the the standp'ipe 11, thus causing a fresh charge of air to.

collect above the liquid plug within the standpipe. At the same time, the absolute pressure within the vacuum enclosure will, owing to the suckingof air into the standpipe, have been reduced so that the new liquid column, which replaces the previous column, will be somewhat higher than the latter.

empty a new liquid plug into the standpipe' 11, thus repeating the above-described cycle of operations while pumping out air batchvvise from the vacuum enclosure.

On account of the gradually increasing vacuumz within the vacuum enclosure and within the standpipe 11 com. municating therewith, the downwardly directed force act-- ing on the float 13 due to the vacuum will be increased on completion of each pumping cycle, so that after the discharge of each batch of liquid into the standpipe 11 a greater upward force acting on the float will be required to cause opening of thefloat valve. This'means that the float valve 14, 15 will open at successively increasing liquid levels Within the float vessel 10, whereby successively increasing quantities of liquid will be discharged. into the standpipe so as to form gradually increasing liquid plug lengths in this pipe. It is possible, by suitably dimensioning the float vessel and float, to establish a condition in which, during each valve-opening operation there will only be discharged into the standpipe a quantity of liquid suflicient to form a plug of the length necessary having regard to thevacuum actually reached in the enclosure, whereby a high pumpingeificiency may be expected.

One pre-requisite for satisfactory operation of the.

vacuum producer described resides, of course, in that the liquid supplied in metered quantities from the float vessel into the .standpipe will actually fill out the cross-sectional area of the s-tandpi'pe and will. drop down through this pipe as a perfectly integral liquid plug which forms a sealing partition, between the vacuum enclosure and: the

body of air entrapped below the descending liquid. In

the embodiment shown, an immediate and perfect fillingout of the standpipe cross-sectional area without any admixture of air has been providedfor by causing. the float When a suflicient liquid quantity has again collected in the float'vesse'l 10, the latterwill at a sufficiently rapid rate once the valve has commenced its opening movement.

'A sudden increase ofthe valve-opening force before the valve cone has begun to move offits seat may be attained by supplementing the design of the float valve 7 arrangement in the manner illustrated in FIGURE 4,

As shown in this figure, a tilting vessel 23 known per se,.is mounted on the top of the float 13. This vessel is tiltable about a horizontal pivot axis 24' and comprises two identical pockets 25 and 26 symmetrically disposed relative to the, tilting axis. Either of the pockets 25, 26 is always positioned below a spout 27 through which a suitably metered small proportion of the amount of liquid supplied through the inlet'pipe 17. is allowed to flow into said pocket. The rate of outflow through the spout 27 i is suitably metered in such a way as to cause the pocket to be completely filled immediately before the liquid Within the float vessel 10 has reached a level at which the lift exerted onthe float is just ,suflicient, to outweigh 7 rapid rate thus completely opening the passageway be- Valve 14, 1-5 controlling the liquid discharge into the pipe 7 to be maintained submerged in the liquidwithin the float vessel 10. By forming the bottom portion of the float substantially asa cone, the liquid iscausedto flow radially inward towards the mouth of the pipefrom all sides, so that right from the beginning there will form a solid plug in the standpipe, provided the valve openingftakes place 'that the valve is caused to reopen momentarily.

the sum of the. forces tending to move the float in a downward direction. As soon as the. pocket, e.g.' pocket 26, disposed beneath the-spout has been filled up to a predetermined level, the vessel 23 will tilt, thus dischargingthe liquid gathered inthis pocket into the float vessel 10 whilst simultaneously positioning the other pocket, e.-g. pocket 25', beneath thev spout. The emptying of the pocket 26 will cause a sudden decrease of the downward force acting on the float 13' by the weight of the liquid quantity thus discharged, and at the same time 'a sudden increase in the. liquid level within the float vessel will occur. As a result, the float will move upwardly at a tween the float vessel. 10v and the standpipe 11.

It is a desideraturn alsov that, once the valve has closed, it shall remain closed until the next-succeeding metereddischarge is to be initiated- As, is well known, a floatcont-rolled discharge valve moves towards its seating at an accelerated rate immediately before it engages the same; The cause of this effect resides in a pressure reduction in the liquid due to itsvelocity,. the so-called Bernoullis pressure reduction. As soon. as the valve closes, this pressure reduction'will cease, and at the same time the liquid mass displaced by the float is increased, so In order to prevent such oscillation of the valve in. conjunction with its closing, the apparatus may be supplemented with a damping or inertia mechanism of any suitable construction, which may be known per se.

Where the internal diameter of thestandpipe is so large that the capillary forces cannot play any effective part in the maintaining of the plug in a. coherent state, a certain falling velocity of the liquid plug will be required to keep the same together as a unit during its -movement through the standpipe. The minimurnfalling velocity will be the higher, the larger is the diameter of the standpipe. As already stated, it will be necessary, in order to obtain a sufficient falling velocity of the plug,

. to discharge each time a liquid quantity so proportioned as to cause. the length of the plug for-medto exceed the height of the liquid column present in the lower portion of the s-tandpipe.

Particularly in large installations it may be suit-able, for controlling the liquid dosage or apportioning valve, to employ, instead of a float,'a special mechanism adapted to open the valve when a suflicient quantity of liquid has collected in the vessel for. forming a liquid plug of the desired length, and to cause closure of the valve afiter the elapse of a time the length ofwhich is properly related to the vacuum actually existing in the vacuum enclosure. Such a mechanisrmif suitably constructed, maybe op 'erated utilizing the potential energy of the liquid proper;

flow freely to the float vessel inlet. The vacuum producer illustrated in said figure is thus intended primarily for utilizing the potential energy of bath water, slops and other dirty water let out into a sewerage system from the upper floors of a building.

According to FIGURE 5, the float vessel is provided with a tight-fitting cover 29 so that the interior of the vessel is hermetically enclosed and thus separated from the ambient air. The cylindrical wall of the vessel is formed at a short distance beneath the cover 29 with a circumferential row of spaced openings each having connected to it in a gas tight manner a corresponding one of a plurality of liquid inlet pipes 30, which are preferably made of flexible plastic tubing. Each pipe 30 is provided at its opposite end with a normally closed valve, for instance a float-operated valve 31. Disposed underneath the cover 2? is a cylindrical baffle or skirt 32 adapted to prevent liquid entering through the respective pipes 30 from impinging on the float 13. The balfle also serves as a guide for the float. In order to promote the conveyance of the liquid from the respective wash basins or the like to the float housing 10 disposed at the same floor a certain vacuum is maintained within this housing. The absolute pressure within the float housing 1%, however, must be substantially in excess of the absolute pressure within the vacuum enclosure and its associated bran-ch pipe 13 in order to enable the float valve to function in the manner described in conjunction with FiG- URES 1, 2 and 3. Such a reduced vacuum is maintained within the float vessel 10 by the provision of a bypass 33 through which the air space of said vessel is connected with the branch pipe 18 and which contains a pressure control valve 34 adapted to close automatically as the difference between the pressures on either side of the valve drops below a predetermined value.

Referring to FIGURE 8 which illustrates the pressure control valve 34 in the pipe 33, there is included a nipple 78 in which a circumferential valve seating 79 is provided. A non-return valve member in the form of a flap 80 is fixedly attached to a pin 81 rotatable in a projection 82. of the nipple 7%. That portion of the pin 81 which is rot-atably mounted in the projection 82 is of circular cross-section and adapted to provide a seal against the projection.

The pin 81 projects on the outside of the projection 32 and has mounted thereon a lever arm 83 that is secured by a pin 84. A weight 85 is attached to the arm 83 and is displaceable therealong to provide an adjustable moment about the pin 81. The weight may be fixed in position by a set screw 86.

It will be apparent that the valve member 89 retains the passage through the nipple 78 closed as long as the pressure difference acting on the valve member produces a clockwise moment about the pin 31 that is less than the counterclockwise moment about the pin produced by the weight 85. Thus, when the pressure within the float vessel It) exceeds that in the branch pipe 18 by an amount suflicient to produce a clockwise moment about the pin 81. greater than the counterclockwise moment produced by the weight 85, the valve member 81 is swung to an open position, allowing the pressure within the housing 10 to be reduced until the valve member swings closed.

The above-mentioned float valve 31 disposed at said opposite end of each liquid inlet pipe 30 comprises, as seen in FIGURE 5, a float housing 35 and, disposed therein, a float 36 mounted for vertical movements within the float housing by being guided between ribs 37 provided therein. In the lowermost position of the float, as shown in the drawing, its conioally shaped bottom end sealingly engages a correspondingly shaped seating formed at the junction between the housing and a pipe socket 39 to which the above-mentioned plastic tube 30 leading to the float vessel 1! is connected, whilst in its uppermost position the float abuts a distributing plate 41 mounted in spaced relation with the underside of the float-housing cover. Through a pipe socket 41 provided centrally in the latter, the float housing 35 may be connected to the outlet conduit from a wash basin 42 or the like, so that liquid will flow into the float housing and will lift the float when the bottom outlet of the wash basin is opened. Each time this occurs, liquid will be sucked through the conduit 30 into the float vessel 10 of the vacuum producer. When the wash basin 42 has been emptied, and the liquid level within the float housing 35 of the cut-off valve 31 has fallen off sufliciently to cause this valve to close, the inflow of liquid into the float vessel 10 is interrupted. As the liquid enters and begins to fill the float vessel 10, a corresponding amount of air is sucked out through the valve 34 whereby the vacuum within the float vessel 10 is maintained substantially constant. In a similar way, liquid is sucked batchwise into the float valve housing 10 through the inlet pipe 30 from any other Wash basin or the like connected thereto. As the free liquid surface within the float housing 10 has risen to a level determined by the vacuum existing in the branch pipe 18, the float 13 is rapidly unseated and suddenly discharges the collected quantity of water into the standpipe 11, and then re-closes before the float housing has become completely emptied of its liquid content, as described in conjunction with the embodiment shown in FIGURES 1 to 3.

The above-described vacuum producer comprising a sealed-off float vessel 10 and a standpipe 11 the lower end of which is immersed into liquid 12 is obviously dependent, for its proper operation, on the maintenance of a certain minimum vacuum value within the vacuum enclosure or tank which is common to a plurality of apparatus and with which the branch pipe 18 communicates. To the end of removing such dependence, there is mounted, according to FIGURE 5, within the branch pipe 18, beyond the point where the by-pass conduit 33 opens into this branch pipe, a cut-off valve generally designated by 45 and adapted to close automatically if the vacuum within the float vessel 10 should drop below a predetermined value. The valve 45 is shown in the drawing as a butterfly valve pivoting about the axis 46 and urged towards its closed position by the action of a weight-loaded lever 47. The lever 47, however, is normally held in a raised position corresponding to the open position of the valve by a piston 48 adapted to slide within a cylinder 49 and connected to the lever by a link 50. The cylinder space above the piston communicates with the air space of the float housing 10 through a pipe 51 whereby, as long as a vacuum of suflicient magnitude exists Within the float housing, the piston is retained in its upper limit position, as shown, whereas, if the air pressure within the float housing should exceed said predetermined value, the piston will descend through its cylinder and thus cause the valve to close.

A pre-requisite for the possibility of utilizing the potential energy or head of slops and other waste Water for vacuum production while using comparatively narrow conduits is, of course, that such water is relatively free from solid refuse or excrements discharged from water closets. FTGURE 6 illustrates a complete building sewage handling system in which the vacuum produced by utilizing the waste water head is used for the conveyance of the refuse from the water closets through a separate conduit system to a collecting tank under vacuum, whereas the ordinary waste water is conducted to the sewerage system through vacuum production apparatus constructed in accordance with the present invention.

Referring to said FIGURE 6, numeral 52 designates a vacuum enclosure or tank, numeral 53 denotes two vacuum producers of the kind shown in FIGURE 5 and mounted at the second and third floors, respectively, and numeral 54 denotes a bath tub, 55 a wash stand and 56 a dish-washing sink at the respective floors. Each vacuum producer 53 is connected to the building sewer 57 by an individual standpipe 11, whilst a pipe 58 common floors are connected, through individual float-controlled valves of the kind illustrated in FIGURE 5, to conduits 30 which open into the float vessel 10 of the respective vacuum producers, as shown in FIGURE 5. Thosebath tubs, wash stands and sinks which are installed at the bottom floor may also be similarly connected, by a con? duit 30, to a closed collectingvessel 59 within which a vacuum which ensures liquid flow through a conduit rising in the direction of flow therethrough is maintained in the same way as Within the float housings of the vacuum producers 53. The vessel 59 is provided with a floatcontrolled bottom valve through which the collected waste water is intermittently discharged into the sewer 57- through an outlet conduit 60.

sil s The vacuum produced within the vacuum tank 52 is utilized, in addition to its utilization for sucking the bath water and other waste 'water through the relatively narnarrow discharge outlet pipe 62 to a closed collecting or' disposal tank 63 which is connected to the vacuum tank 52 through a pipe 64 and in which, therefore, a vacuum permanently exists. Such a water closet system is dis-v closed in my copending application Serial No.1 84,632 filed March 22, 1962. 7

FIGURE 7 illustrates a vacuum producer of the type shown in'FIGURES l to 3, ie having an openrto'pped float vessel, which is arranged for utilizing the, potential energy or head of the water in a high-level natural water reservoir for theproduction of a vacuum within anenclosure, or closed tank. 7 v

In this figure, as before, numeral '10 designates the float vessel or housing, numeral 11 the standpip'e,-numeral 12 a lowerrlevelbody of water intowhich said pipe is immersed, numeral 18'the branch pipe and numeral 19 the nonrreturn valve inserted therein, adjacent to the stand pipe. The vacuum tank to which the branch pipe 18 connects is designated by 65. Numeral 66 diagrammatically indicates a weir extending, for instance, across a river. Formed through the weir 66, which forms one lateral wall of the float vessel, 10, is an opening 67 which is controllable by a flap 69 pivotable about an axis 68. Through the inlet opening 67 water continually flows from V the reservoir upstream of the weir into the float vessel at a rate of flow'corresponding to the etlective opening area provided by the flap 69. float vessel is discharged periodically into the standpipe 11 under the control of the float 13, as described hereinbefore in conjunction with FIGURES l to 3', thus creating each time inthestandpipe a liquid plug or piston causing a quantity of air to be sucked out fromthe vacuum tank 65 whereby the air pressure therein is gradually reduced. After a desired degree of vacuum has been reached within the vacuum tank, the operation of the serving as a counter-weigh During this movement the cam member 74 urges the roller 75 to move continuously to the rightaccording to the figure, whereby the flap is pivoted. continuously towards its closed positionwhich it reaches as. the maximum vacuum desired has been reached. As the vacuum diminishes again this causes downward movement of the pistonv 72 together With'the being 'usedas a counterweight a chain orthe like could be used, such chain being fastened at one end to the piston 72 and supported at its lower end on a stationary base whereby the length of the chain part. hanging down from the piston will increase as the piston moves upward into the cylinder. 1

Inc standpipe 11, which might be inclined at a relatively small angle to the horizontal. and thus may have considerable length, may be 'formed with one or more plug-restoration pockets or loops 77. Similar pockets or loops could of course be associated also with ,the stand- The liquid collected within the .as recited in cla1rn 2 wherein said collecting vessel is a vacuum producer should desirably be stopped, orits rate of operation should at least be reduced. In order to enable an automatic adaptation of said rate of operation to the momentary requirements, aregulating mechanism is provided comprising a vertical cylinder '70 which is connected at its top end to the vacuum tank through a pipe 71 and in which reciprocates a piston 72 having a pipes'of otherv constructional forms. of the vacuum pump according to the invention.

What I claim is; 1. A building sewerage system forcarry ing away waste water, comprising waste water receivingrapparatus having an outlet, a hermetically sealed collecting vessel, means for maintaining a sub-atmospheric pressure'in said collecting vessel, conduit means connecting the outlet of said waste water receiving apparatus to said collecting vessel, 2. shutoff valve inserted in said conduit means, means for movwhich waste Water is to be carried a collecting vessel.

'having an inlet and an outlet, conduit means coupling said inlet of said collecting vessel to an outlet of said waste water discharging apparatus and through which said waste water flows from. said'waste water discharging apparatus to saidcollecting vessel, a sealed enclosure coupled to the outlet of said collecting vessel, 2. cut-01f valve positioned in the outlet of said collecting. vessel between the collecting vessel and the point at which the enclosure is coupled to said outlet, means for opening said cut-off valve when the waste water in said collecting vessel rises to a first predetermined level, and means for closing Sald: cut-cit valve when the waste water in said collecting vessel falls to a second level lower than said first level, whereby a vacuum is produced in the enclosure upon the discharge of waste water through the outlet of said collecting vessel and the waste water in the collecting vessel is periodically discharged.

3. In combination with a building sewerage system sealed enclosure, a line coupling the vacuum enclosure to said collecting vessel through a cut-01f valve whereby a vacuum is produced insaid collecting vessel and is held at a predetermined value.

4. A building sewerage system for-carrying away waste water, comprisingwaste water discharging apparatus from which waste water isto be carried, a hermetically sealed pressure exists within the vacuum tank :65, the flap is wide open. 'As the vacuum increases within the tank 65, the piston 72 issucked further into the cylinder 70 pulling at the same time behind it a water column 76 collecting vessel having, an inlet and an outlet, conduit means coupling said inlet of said, collecting vessel to an outlet of said waste water discharging appparatus, a sealed enclosure coupled to the outlet 'of said collect-ing vessel, a first cut-off valve positioned in said conduit means, a second'cut-ofi valve positioned in the outlet of said collecting vessel between the collecting vessel and the point at which the enclosure is coupled to said outlet, means responsive to the discharge of liquid through the outlet of said waste water discharging apparatu for opening said first cut-oil valve, means for opening said second cut-off valve when the liquid in said collecting vessel rises to a first predetermined level, and means for closing said second cut-oil valve when the liquid in said collecting vessel falls to a second level lower than said first level, whereby a vacuum is produced in the enclosure upon the discharge of liquid through the outlet of said collecting vessel.

5. In combination with a building sewerage system as recited in claim 4, pipe means coupling a space above the liquid in said collecting vessel to said enclosure, and valve means positioned within said pipe means for maintaining the pressure in said space in said collecting vessel at a pressure greater than the pressure in said enclosure and less than atmospheric pressure.

6. A building sewerage system for carrying away waste water, comprising waste water receiving apparatus having an outlet, a hermetically sealed collecting vessel, means for maintaining a sub-atmospheric pressure in said collecting vessel and for discharging the contents of said collecting vessel, pipe means connecting the outlet of said waste water receiving apparatus to said collecting a vessel, a shut-oil valve inserted in said pipe means, means for moving said shut-olf valve from a closed to an open position in response to the discharge of liquid from said waste water receiving apparatus and to reclose said shutoff valve when said discharge ceases, and an outlet from said collecting vessel, wherein said means for maintaining a sub-atmospheric pressure in said collecting vessel and for discharging the contents of said collecting vessel comprises a downwardly extending discharging standpipe coupled at its upper end to the outlet of said collecting vessel, means for discharging water batchwise from said collecting vessel to form integral plugs of Water completely filling out the cross-sectional area of said standpipe, and pipe means connecting said collecting vesi0 sel to the upper end of said standpipe, whereby, as said plugs of water gravitate through said standpipe, the air is sucked out of said collecting vessel.

7. In combination with the building sewerage system as recited in claim 6, a vacuum enclosure connected to the upper end of said standpipe, whereby, as said plugs of water gravitate through said standpipe, the air is sucked out of said vacuum enclosure.

8. A building sewerage system for carrying away Waste water, comprising waste water receiving apparatus having an outlet, a hermetically sealed collecting vessel, means for maintaining a sub-atmospheric pressure in said collecting vessel, pipe means connecting the outlet of said waste water receiving apparatus to said collecting vessel, a shut-off valve inserted in said pipe means, said shutoff valve comprising a float disposed in a hermeticallysealed float housing through which the discharged waste water flows, mean-s for moving said shut-cit valve from a closed to an open position in response to the discharge of liquid from said waste water receiving apparatus and to reclose said shut-off valve when said discharge ceases, an outlet from said collecting vessel, and means to dis charge the contents of said collecting vessel.

9. A building sewerage system according to claim 8, wherein said float housing is in the form of an upright elongated cylinder having a bottom opening controlled by said float.

Reterences Qited by the Examiner UNITED STATES PATENTS 263,147 8/82 Edison 230l07 264,329 9/82 Muller 230-407 377,681 2/88 Le Marquand 137236 439,687 11/90 Reid 420'5 482,439 9/92 Liernur 137-236 M. CARY NELSON, Primary Examiner.

EDWARD V. BENHAM, Examiner, 

1. A BUILDING SEWERAGE SYSTEM FOR CARRYING AWAY WASTE WATER, COMPRISING WASTE WATER RECEIVING APPARATUS HAVING AN OUTLET, A HERMETICALLY SEALED COLLECTING VESSEL, MEANS FOR MAINTAINING A SUB-ATMOSPHERIC PRESSURE IN SAID COLLECTING VESSEL, CONDUIT MEANS CONNECTING THE OUTLET OF SAID WASTE WATER RECEIVING APPARATUS TO SAID COLLECTING VESSEL, A SHUTOFF VALVE INSERTED IN SAID CONDUIT MEANS, MEANS FOR MOVING SAID SHUT-OFF VALVE FROM A CLOSED TO AN OPEN POSITION IN RESPONSE TO THE DISCHARGE OF LIQUID FROM SAID WASTE WATER RECEIVING APPARATUS AND TO RECLOSE SAID SHUT-OFF VALVE WHEN SAID DISCHARGE CEASES, AN OUTLET FROM SAID COLLECTING VESSEL, AND MEANS TO DISCHARGE THE CONTENTS OF SAID COLLECTING VESSEL, WHEREIN SAID CONDUIT MEANS COMPRISES FLEXIBLE TUBES OF PLASTIC MATERIAL. 